Treatment apparatus, treatment method and storage medium

ABSTRACT

An apparatus for accurately determining if a substrate is properly retained by a substrate-retaining mechanism. The apparatus includes a substrate-retaining mechanism to retain a wafer, a treatment liquid supply mechanism to supply a treatment liquid to the wafer, and a rotatable cup adapted to rotate as an integral unit with the substrate-retaining mechanism while covering the outer peripheral portion of the wafer. The substrate-retaining mechanism has a retaining member with two ends. If the first end retains a wafer, the second end is in an upper position. If the first end retains no wafer, the second end is in a lower position. A touch sensor is arranged below the second end of the retaining member so that, when the second end is in the lower position, the second end makes contact with the touch sensor.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an apparatus and a method for determining whether or not a treatment target substrate is being retained by a substrate-retaining mechanism, and a storage medium for executing the method by a computer.

2. Description of the Prior Art

It has been known in the art a Liquid treatment apparatuses including a substrate-retaining mechanism for retaining a treatment target substrate, particularly a semiconductor wafer (hereinafter, referred to as a wafer), a treatment liquid supply mechanism for supplying a treatment liquid to the treatment target substrate retained by the substrate-retaining mechanism, and a rotation mechanism for rotating the substrate-retaining mechanism that retains the wafer. Such conventional liquid treatment apparatuses have a light-emitting unit positioned above the substrate-retaining mechanism to emit light, and a light-receiving unit positioned below the substrate-retaining mechanism to receive light from the light-emitting unit. As a result, the apparatuses can determine whether or not a wafer is being retained by the substrate-retaining mechanism.

Particularly, it is determined that no wafer is being retained by the substrate-retaining mechanism if light from the light-emitting unit is detected by the light-receiving unit. It is determined that a wafer is being retained by the substrate-retaining mechanism if no light from the light-emitting unit is detected by the light-receiving unit.

Although, the conventional liquid treatment apparatuses can determine whether or not a wafer exists on the substrate-retaining mechanism, they cannot determine whether or not the wafer is being properly retained by the substrate-retaining mechanism.

In addition, it may be erroneously determined that a wafer exists on the substrate-retaining mechanism when a chemical liquid or moisture adheres to the light-receiving unit and prevents it from receiving light from the light-emitting unit. In order to avoid such an erroneous determination, the light-receiving unit needs to be made of an expensive material (e.g. sapphire) that does not react with chemical liquids. This increases the cost for manufacturing the liquid treatment apparatuses.

Furthermore, even if the wafer has been fractured while being rotated by the rotation mechanism, the fracture cannot be instantly detected, and fragments of the wafer may damage components (particularly, valves) of the liquid treatment apparatuses, making it inevitable to repair or replace the damaged components.

SUMMARY OF THE INVENTION

Accordingly, the present invention has been made to solve the above-mentioned problems. The present invention provides a treatment apparatus capable of accurately determining whether or not a treatment target substrate is being properly retained by a substrate-retaining mechanism without errors, capable of being manufactured at a low cost, and capable of instantly detecting fracture of the treatment target substrate during treatment. The present invention further provides a treatment method using the treatment apparatus, and a storage medium for executing the treatment method by a computer.

In accordance with an aspect of the present invention, a treatment apparatus comprises a casing, a substrate-retaining mechanism positioned inside the casing to retain a treatment target substrate, a treatment liquid supply mechanism to supply a treatment liquid to the treatment target substrate retained by the substrate-retaining mechanism, and a rotation mechanism to rotate the substrate-retaining mechanism. The substrate-retaining mechanism has a retaining member adapted to pivot about a pivot shaft during a substrate retaining operation. When a first end of the retaining member retains the treatment target substrate, a second end of the retaining member is in a normal position. When the first end of the retaining member does not retain the treatment target substrate, the second end is in an abnormal position. A touch sensor is arranged adjacent to the second end of the retaining member. When the second end of the retaining member is in the abnormal position, the touch sensor can touch the second end of the retaining member.

The treatment apparatus can accurately determine whether or not the treatment target substrate is properly retained by the substrate-retaining mechanism, and substantially reduce a manufacturing cost. In addition, any fracture of the treatment target substrate during treatment can be detected instantly.

The touch sensor may have a touch portion having flexibility. The touch portion is adapted to touch the second end of the retaining member. A sensor portion connected to the touch portion detects a movement of the touch portion.

The touch portion may have a protrusion protruding toward the retaining member so that the protrusion can touch the second end of the retaining member. The protrusion is replaceable. Thus, even if the protrusion is damaged by the impact resulting from contact with the second end of the retaining member rotating at a high rate, the protrusion is simply replaced. Accordingly, the maintaining cost of the liquid treatment apparatus can be reduced.

The sensor portion is preferably installed outside the casing. Thus, even if the sensor portion is not subjected to waterproofing treatment, it is not damaged by the treatment liquid.

In the present invention, the treatment apparatus may further include a control mechanism to control at least the rotation mechanism. The control mechanism rotates the substrate-retaining mechanism once at a rate lower than a rotation rate when the treatment target substrate is treated, after the treatment target substrate has been retained by the substrate-retaining mechanism. Thus, it can be checked whether or not the treatment target substrate is properly retained by the substrate-retaining mechanism. Thus, whether or not the treatment target substrate is properly retained by the substrate-retaining member can be determined by arranging the touch sensor in one position below the second end of the retaining member.

In accordance with another aspect of the present invention, a treatment method using a treatment apparatus comprises retaining a treatment target substrate by a substrate-retaining mechanism positioned inside a casing, checking whether or not the treatment target substrate is properly retained by the substrate-retaining mechanism by rotating the substrate-retaining mechanism once at a rate lower than a rotation rate when the treatment target substrate is treated, rotating the treatment target substrate retained by the substrate-retaining mechanism by a rotation mechanism, and supplying a treatment liquid to the treatment target substrate retained by the substrate-retaining mechanism by a treatment liquid supply mechanism. The substrate-retaining mechanism has a retaining member adapted to pivot about a pivot shaft during a substrate retaining operation, a second end of the retaining member is in a normal position when a first end of the retaining member retains the treatment target substrate and, the second end of the retaining member is in an abnormal position when the first end of the retaining member does not retain the treatment target substrate. A touch sensor is arranged adjacent to the second end of the retaining member and the touch sensor is able to touch the second end of the retaining member when the second end of the retaining member is in the abnormal position.

This method can accurately determine whether or not the treatment target substrate is properly retained by the substrate-retaining mechanism, decrease the manufacturing cost of the treatment apparatus, and instantly detect any fracture of the treatment target substrate during treatment. In addition, the method can determine whether or not the treatment target substrate is properly retained by the substrate-retaining member by arranging the touch sensor in one position below the second end of the retaining member.

In accordance with another aspect of the present invention, a storage medium storing a computer program for executing a treatment method by a computer is provided. The treatment method using a treatment apparatus comprises retaining a treatment target substrate by a substrate-retaining mechanism positioned inside a casing, checking whether or not the treatment target substrate is properly retained by the substrate-retaining mechanism by rotating the substrate-retaining mechanism once at a rate lower than a rotation rate when the treatment target substrate is treated, rotating the treatment target substrate retained by the substrate-retaining mechanism by a rotation mechanism, and supplying a treatment liquid to the treatment target substrate retained by the substrate-retaining mechanism by a treatment liquid supply mechanism. The substrate-retaining mechanism has a retaining member adapted to pivot about a pivot shaft during a substrate retaining operation, a second end of the retaining member is in a normal position when a first end of the retaining member retains the treatment target substrate, and the second end of the retaining member is in an abnormal position when the first end of the retaining member does not retain the treatment target substrate. A touch sensor is arranged adjacent to the second end of the retaining member and the touch sensor is able to touch the second end of the retaining member when the second end of the retaining member is in the abnormal position.

This storage medium can accurately determine whether or not the treatment target substrate is properly retained by the substrate-retaining mechanism, decrease the manufacturing cost the treatment apparatus, and instantly detect any fracture of the treatment target substrate during treatment. In addition, the storage medium can determine whether or not the treatment target substrate is properly retained by the substrate-retaining member by arranging the touch sensor in one position below the second end of the retaining member.

According to the present invention, when the first end of the retaining member is retaining a treatment target substrate, the second end of the retaining member is in the upper position. Alternatively, when the first end of the retaining member is retaining no treatment target substrate, the second end of the retaining member is in the lower position. A touch sensor is arranged below the second end of the corresponding retaining member. Thus, when the second end of the retaining member is in the lower position, the touch sensor touches the second end. Thus, it is possible to accurately determine whether or not the treatment target substrate is being properly retained by the substrate-retaining mechanism without errors. Further, the cost for manufacturing the treatment apparatus is low. Furthermore, any fracture of the treatment target substrate during treatment can be detected instantly.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a top view of a liquid treatment system including liquid treatment apparatuses according to an embodiment of the present invention.

FIG. 2 is a longitudinal sectional view of a liquid treatment apparatus according to an embodiment of the present invention.

FIG. 3 is a magnified longitudinal sectional view of a liquid treatment apparatus according to an embodiment of the present invention.

FIG. 4 is a longitudinal sectional view of a mechanism for retaining a wafer by a retaining member of a liquid treatment apparatus according to an embodiment of the present invention.

FIG. 5 is a magnified longitudinal sectional view of a liquid treatment apparatus with the periphery of its touch sensor according to an embodiment of the present invention.

DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS

Hereinafter, a treatment apparatus, a treatment method, and a storage medium according to an embodiment of the present invention will be described with reference to the accompanying drawings. FIG. 1 to FIGS. 5( a) and (b) show an embodiment of the present invention.

As shown in FIG. 1, a liquid treatment system includes a loading table 81 for loading a carrier, which has received a treatment target substrate, particularly a wafer W, from an outside, a transfer arm 82 for taking the wafer W out of the carrier, a stacking unit 83 for stacking the wafer W taken by the transfer arm 82, and a main arm 84 for transferring the wafer W from the stacking unit 83 into the a liquid treatment apparatus 1. The liquid treatment system includes a plurality of (twelve, according to the present embodiment) the liquid treatment apparatuses 1. FIG. 1 is a top view of the liquid treatment system including the liquid treatment apparatuses 1 according to the present embodiment.

As shown in FIG. 2, each liquid treatment apparatus 1 includes a casing 5, a substrate-retaining mechanism 20 positioned inside the casing 5 to retain a wafer W, a treatment liquid supply mechanism 30 to supply a treatment liquid to the wafer W retained by the substrate-retaining mechanism 20, a rotatable cup 61 adapted to rotate as an integral unit with the substrate-retaining mechanism 20 while covering the outer peripheral portion of the wafer W retained by the substrate-retaining mechanism 20 inside the casing 5, and a rotation mechanism 70 to integrally rotate the rotatable cup 61 and the substrate-retaining mechanism 20. FIG. 2 is a longitudinal sectional view of the liquid treatment apparatus 1 according to the present embodiment.

As shown in FIG. 2, an annular discharged-liquid cup 62 is arranged outside the peripheral portion of the rotatable cup 61 inside the casing 5 to collect the treatment liquid that has been used to clean the wafer W. A discharged-liquid tube 63 is connected to the discharged-liquid cup 62 to discharge the treatment liquid went through the discharged-liquid cup 62.

As shown in FIG. 2, the casing 5 has an opening 5 a formed on its sidewall so that the wafer W can move into/out of the casing 5.

As shown in FIGS. 2 and 3, the substrate-retaining mechanism 20 includes a rotatable plate 21 having a disk shape and horizontally positioned, a retaining member 22 positioned on the end of the peripheral portion of the rotatable plate 21 to retain the wafer W at the first end 22 a, and a cylindrical rotation shaft 23 extending vertically and downwardly while being connected to the center of the lower surface of the rotatable plate 21. A circular hole 21 a is formed at the center of the rotatable plate 21 and is communication with a hole 23 a of the cylindrical rotation shaft 23. An elevating member 25 is positioned inside the hole 23 a of the rotation shaft 23 and is adapted to freely move upwardly/downwardly by means of an elevating mechanism 56.

As shown in FIGS. 4 a to 4 c, an elevating mechanism 15 is arranged below the second end 22 b of each retaining member 22 and is adapted to move freely and upwardly/downwardly. When a wafer W is received in the wafer-retaining position of the retaining member 22, the elevating member 15 forces the second end 22 b of the retaining member 22 upward, and when the wafer W is retained by the retaining member 22, the elevating mechanism 15 moves away from the second end 22 b of the retaining member 22.

The retaining member 22 is adapted to pivot about a pivot shaft 17 upwardly/downwardly, as shown in FIGS. 4 a to 4 c. A spring 16 is positioned between the retaining member 22 and the rotatable plate 21. Thus, the second end 22 b of the retaining member 22 is in the lower position when no wafer W is being retained and when the second end is not being forced by the elevating mechanism 15 (refer to FIG. 4 a). The second end 22 b of the retaining member 22 is in the upper position when no wafer W is being retained and when the second end is being forced by the elevating mechanism 15 (refer to FIG. 4 b). In addition, the retaining members 22 are arranged at three points in the circumferential direction so that the wafer W is retained at the three points.

In the case of a wafer retaining operation (i.e. after a wafer W has been retained), if the first end 22 a of the retaining member 22 is retaining the wafer W (normal condition), the second end 22 b is in the upper position (refer to FIG. 5 a). If the first end 22 a of the retaining member 22 is retaining no wafer W (abnormal condition), the second end 22 b is in the lower position (refer to FIG. 5 b).

As shown in FIGS. 2 and 3, a rear surface treatment liquid supply channel 26 is formed inside the elevating member 25 to supply a treatment liquid from the rear surface (lower surface) of the wafer W. A wafer support table 27 is positioned on the upper end of the elevating member 25, and a wafer support pin 28 is positioned on the upper surface of the wafer support table 27 to support the wafer W. The rotation shaft 23 is rotatably supported on a base plate 6 via a bearing member 29.

As shown in FIG. 2 to FIGS. 5( a) and (b), a touch sensor 10 is positioned below the second end 22 b of the retaining member 22 away from the operating position of the elevating mechanism 15. Thus, when the retaining member 22 is conducting neither a wafer retaining operation nor a wafer releasing operation, and when the second end 22 b of the retaining member 22 is in the lower position in an abnormal manner, the touch sensor 10 can touch the second end 22 b of the retaining member 22.

More particularly, as shown in FIG. 2 to FIGS. 5( a) and (b), the touch sensor 10 has a contact portion 11 made of resin having flexibility and adapted to touch the second end 22 b of the retaining member 22, and a sensor portion 13 connected to the touch portion 11 via a connection portion 12 to detect the movement of the touch portion 11. The touch portion 11 has a protrusion 11 a protruding toward the retaining member 22 in the horizontal direction. The protrusion 11 a is adapted to touch the second end 22 b of the retaining member 22 and is replaceable.

As shown in FIGS. 2 and 3, the sensor portion 13 is positioned outside the casing 5, more particularly beneath the base plate 6 outside the casing 5. Although the connection portion 12 extends through the base plate 6, the space between the base plate 6 and the connection portion 12 is sealed so that the treatment liquid supplied to the wafer W does not leak through the sensor portion 13. This means that, even if the sensor portion 13 is not subjected to waterproofing treatment, it is not damaged by the treatment liquid.

As shown in FIG. 2, the rotation mechanism 70 includes a motor 71 having a motor shaft 71 a, and a belt 72 wound around the corresponding motor shaft 71 a and around the lower end of the rotation shaft 23. A pulley 74 is positioned between the belt 72 and the motor shaft 71 a, and another pulley 73 is positioned between the belt 72 and the rotation shaft 23.

As shown in FIG. 2, the treatment liquid supply mechanism 30 includes a nozzle block 31 having a nozzle 31 a to supply a treatment liquid to the surface of the wafer W retained by the substrate-retaining mechanism 20, a nozzle arm 32 connected to the nozzle block 31 to move the corresponding nozzle block 31 along the surface of the wafer W retained by the substrate-retaining mechanism 20, a nozzle pivot shaft 33 extending in the vertical downward direction from the corresponding nozzle arm 32, and a nozzle driver 75 to drive the corresponding nozzle pivot shaft 33. A nozzle elevating mechanism 57 is connected to the lower end of the nozzle pivot shaft 33 to drive the nozzle block 31, the nozzle arm 32, the nozzle pivot shaft 33, and the nozzle driver 75 upward/downward.

The nozzle driver 75 includes a motor 76 having a motor shaft 76 a, and a belt 77 wound around the corresponding motor shaft 76 a and around the lower end of the nozzle pivot shaft 33. A pulley 79 is positioned between the belt 77 and the motor shaft 76 a, and another pulley 78 is positioned between the belt 77 and the nozzle pivot shaft 33.

A control mechanism 50 is connected to the rotation mechanism 70, to the nozzle driver 75 of the treatment liquid supply mechanism 30, or to the treatment liquid supply unit 40 (described later) to control the driving of these components. The control mechanism 50 is adapted to control the rotation mechanism 70 so that, after a wafer W has been retained by the substrate-retaining mechanism 20, the substrate-retaining mechanism 20 is rotated once at a rate lower than the treatment rotation rate, i.e. the rotation rate when the wafer W is processed. The control mechanism 50 is also connected to the touch sensor 10 to receive signals from it.

As shown in FIGS. 2 and 3, an annular discharged-gas cup 66 is arranged outside the peripheral portion of the discharged-liquid cup 62 to receive and then discharge cleaning air, which has been supplied from a gas introduction unit 3 and which has passed through the wafer W. A discharged-gas tube 67 is connected to the discharged-gas cup 66 to discharge gas out of the discharged-gas cup 66. A slit-type through-hole 66 a is formed on the lower end of the discharged-liquid cup 62 to guide the gas from the discharged-gas cup 66 to the discharged-gas tube 67 (refer to the dotted arrow shown in FIG. 2).

As shown in FIG. 2, treatment liquid channels 35, 38 are formed inside the nozzle block 31, the nozzle arm 32, and the nozzle pivot shaft 33 so that the treatment liquid can pass through the channels. As shown in FIG. 2, the treatment liquid channels 35, 38 communicate with the treatment supply unit 40.

The operation of the treatment apparatus according to the present embodiment, which has the above-mentioned construction, will now be described. More particularly, a liquid treatment method for cleaning a wafer W by the liquid treatment apparatus 1 according to the present embodiment will now be described.

A wafer is transferred into the casing 5 of the liquid treatment apparatus 1 via the opening 5 a while being retained by the main arm 84. The transferred wafer W is delivered to the top of the wafer support pin 28 on the wafer support table 27 while the elevating member 25 is lifted. In this state, the second end 22 b of the retaining member 22 is in the lower position (refer to FIG. 4 a).

The elevating mechanism 15 then ascends and forces the second end 22 b of the retaining member 22 upward. As a result, the retaining member 22 pivots about the pivot shaft 17 until the second end 22 b of the retaining member 22 is in the upper position (refer to FIG. 4 b).

The elevating member 25 then descends so that the wafer W is arranged in the wafer-retaining position of the retaining member 22 (refer to FIG. 4 b). The elevating member 15 descends again so that the wafer W is chucked and retained by the first end 22 a of the retaining member 22 (retaining process; refer to FIG. 4 c). Then, the elevating member 15 further descends away from the wafer W.

The control mechanism 50 then controls the rotation mechanism 70 to rotate the substrate-retaining mechanism 20 once at a rate lower than the rotation rate when the wafer W is processed (checking process; refer to FIGS. 2 and 3).

More particularly, the motor shaft 71 a of the motor 71 is rotated to rotate the belt 72, which is wound around the motor shaft 71 a and around the lower end of the rotation shaft 23, and to rotate the rotation shaft 23 once (refer to FIG. 2).

When the retaining member 22 is retaining the wafer W (wafer retaining operation), particularly when the first end 22 a is normally retaining the wafer W, the second end 22 b is in the upper position (refer to FIG. 5 a). When the first end 22 a is not normally retaining the wafer W (abnormal operation), the second end 22 b is in the lower position (refer to FIG. 5 b). In other words, if the wafer W is not properly retained by the retaining member 22, the second end 22 b of the retaining member 22 is placed in the lower position by the elastic force from the spring 16 between the retaining member 22 and the rotatable plate 21 (refer to FIG. 5 b).

Thus, when the wafer W is not properly retained by the retaining member 22, one rotation of the substrate-retaining mechanism 20 causes the second end 22 b of the retaining member 22, which is in the lower position, to touch the protrusion 11 a of the touch portion 11 of the touch sensor 10 (refer to FIG. 5 b). The resulting vibration acting on the touch portion 11 is transmitted to the sensor portion 13. Then, the sensor portion 13 detects that the wafer W is not being properly retained by the retaining member 22. Accordingly, based on the corresponding signal from the sensor portion 13, the control mechanism 50 determines that the wafer W is not being properly retained by the retaining member 22.

In addition, according to the present embodiment, the liquid treatment apparatus determines whether or not a wafer W is being retained by the retaining member 22 by checking whether or not the second end 22 b of the retaining member 22 touches the protrusion 11 a of the touch portion 11 of the touch sensor 10 as mentioned above, instead checking whether or not the light-receiving unit receives light from the light-emitting unit as in the case of conventional liquid treatment apparatus. This avoids the erroneous determination that a wafer W exists on the substrate-retaining mechanism 20, which is unavoidable in the case of the prior art, when a chemical liquid or moisture adheres to the light-receiving unit.

Because no light-receiving unit is used according to the present embodiment, an expensive material (e.g. sapphire) having transmittance and resistance to chemicals is not necessary to manufacture the liquid treatment apparatus 1. Thus, the liquid treatment apparatus 1 can be manufactured at a low cost.

Meanwhile, a method for emitting light in the horizontal direction right above the wafer W may be considered to determine whether or not the wafer W is being normally retained by the substrate-retaining mechanism 20. Particularly, a light-emitting unit may be positioned to emit light in the horizontal direction right above the wafer W, and a light-receiving unit may be positioned to receive light from the light-emitting unit. In this case, it would be determined that the wafer W is being normally retained if the light-receiving unit receives light from the light-emitting unit. Alternatively, it would be determined that the wafer W is not normally being retained if the light-receiving unit receives no light from the light-emitting unit.

This method, however, needs to arrange the light-emitting unit and the light-receiving unit outside the peripheral portion of the casing 5, respectively. Thus, if the discharged-liquid cup is fixed to the casing 5, the discharged-liquid cup may have a hole or a transmitting portion made of sapphire, for example, so that light from the light-emitting unit can pass through.

However, a problem may be caused if this method is applied to the liquid treatment apparatus, as in the case of the present embodiment, which has a rotatable cup 61 adapted to rotate as an integral unit with the substrate-retaining mechanism 20. If the rotatable cup 61 is rotating when the wafer W is being cleaned (refer to the following description), no light from the light-emitting unit can pass through the hole or the transmitting portion. Thus, it cannot check whether or not the wafer W is being normally retained while the wafer W is being cleaned.

It may be considered to form a transmitting portion throughout the entire outer periphery of the rotatable cup 61 to solve this problem. However, use of an expensive material (e.g. sapphire) having both transmittance and resistance to chemicals will increase the manufacturing cost.

In contrast, according to the present embodiment, by providing a touch sensor 10 below the second end 22 b of the retaining member 22, it can check whether or not a wafer W is being retained by the retaining member 22 without providing the rotatable cup 61 with the above-mentioned hole or transmitting portion. This is also the case when the wafer W is being cleaned (refer to the following description). Thus, the present embodiment is particularly useful to a liquid treatment apparatus in which a substrate-retaining mechanism 20 and a rotatable cup 61 are adapted to rotate as an integral unit.

The above-mentioned rotation of the substrate-retaining mechanism 20 at a rate lower than the treatment rotation rate of the wafer W ensures that, even if the wafer W is not being properly retained by the substrate retaining member 20, the wafer W is never damaged. More particularly, assume that that the wafer W is rotated at the same rotation rate as when it is treated to check whether or not the wafer W is being properly retained by the substrate-retaining mechanism 20. The wafer W will be damaged by the impact resulting from the escapement of the wafer W from the retaining member 22 or by the collision between the wafer W escaped from the retaining member 22 and another member, if the wafer W is not properly retained by the retaining member 22. However, this problem is prevented in the present embodiment because the substrate retaining member 20 (and thus the wafer W) is rotated at a rate lower than the treatment rotation rate.

In addition, since the substrate-retaining mechanism 20 is rotated once, one touch sensor 10 is arranged in one position below the second end 22 b of the retaining member 22.

After the above-mentioned checking process is completed, the wafer W retained by the substrate-retaining mechanism 20 is rotated by the rotation mechanism 70 at the treatment rotation rate (rotation process; refer to FIGS. 2 and 3). Since the rotatable cup 61 is integral with the substrate-retaining mechanism 20, rotation of the rotation shaft 23 causes the rotatable cup 61 to rotate as an integral unit with the substrate-retaining mechanism 20.

The treatment liquid supply mechanism 30 then supplies a treatment liquid to the wafer W retained by the substrate-retaining mechanism 20 (treatment liquid supply process; refer to FIG. 2). During this treatment liquid supply process, the wafer W is successively supplied with ammonia peroxide, pure water, hydrofluoric acid and PIA, for example, via the nozzle 31 a.

During this treatment liquid supply process, the nozzle driver 75 drives the nozzle pivot shaft 33, and the nozzle 31 a on the leading end of the nozzle arm 32 pivots about the nozzle pivot shaft 33 above the wafer W along the surface of the wafer W (refer to FIGS. 1 and 2).

If the wafer W is damaged (e.g. cracks) while it is rotated in this manner, the wafer W is displaced relative to the substrate-retaining mechanism 20. As a result, the elastic force from the spring 16 between the retaining member 22 and the rotatable plate 21 causes the first end 22 a of the retaining member 22 to escape from the wafer W, and the second end 22 b of the retaining member 22 moves to the lower position (refer to FIG. 5 b).

As a result, the second end 22 b of the retaining member 22, which is rotating as an integral unit with the substrate-retaining mechanism 20, touches the protrusion 11 a of the touch portion 11 of the touch sensor 10. The sensor portion 13 detects that the wafer W is damaged. As a result, in response to a signal of a corresponding sensor unit 13, the control mechanism 50 stops driving the rotation mechanism 70.

According to the present embodiment, any fracture of the wafer W during cleaning treatment can be detected instantly to stop driving the rotation mechanism 70. This minimizes any damage and prevents fragments of the wafer W from harming components (particularly valves) of the liquid treatment apparatus 1.

Furthermore, a replaceable protrusion 11 a is used and adapted to touch the second end 22 b of the retaining member 22 according to the present embodiment. Thus, even if the protrusion 11 a is damaged by impact resulting from contact with the second end 22 b of the retaining member 22 rotating at a high rate, the protrusion 11 a is simply replaced. This reduces the cost for maintaining the liquid treatment apparatus 1.

In addition, since the rotatable cup 61 rotates as an integral unit with the substrate-retaining mechanism 20, a centrifugal force is applied to a portion of the treatment liquid being away from the wafer W, in response to the contact with the rotatable cup 61. Therefore, the treatment liquid hardly scatters outward and scarcely turns into mist.

After the above-mentioned treatment liquid supply process is completed, the treated wafer W is released from the retaining member 22, removed from the substrate-retaining mechanism 20, and transferred out of the casing 5 via the opening 5 a (refer to FIG. 2).

Although it has been assumed in the above description that the substrate-retaining mechanism 20 is rotated once during the checking process, the substrate-retaining mechanism 20 is not necessary rotated once. However, in order to check whether or not the wafer W is being properly retained by each of the three retaining members 22, the touch portion of the touch sensor needs to extend along the circumference below the second end 22 b of the retaining member 22, for example.

In addition, although the above description has been made with reference to a retaining member 22 adapted to pivot upward/downward, the present invention is not limited to this example. For example, the present invention can be similarly applied to a treatment apparatus employing a retaining member adapted to pivot in the horizontal direction.

Furthermore, according to the present embodiment, it is also possible to provide the above-mentioned liquid treatment method in the form of a computer program to be executed by a computer included in the control mechanism 50, for example, or a storage medium storing such a computer program.

Although an exemplary embodiment of the present invention has been described for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims. 

1. A treatment apparatus comprising: a casing; a substrate-retaining mechanism positioned inside the casing to retain a treatment target substrate and configured to be rotatable while retaining the treatment target substrate; a treatment liquid supply mechanism to supply a treatment liquid to the treatment target substrate retained by the substrate-retaining mechanism; and a rotation mechanism to rotate the substrate-retaining mechanism, wherein the substrate-retaining mechanism has a retaining member with a pivot structure having a first end and a second end each adapted to pivot about a pivot shaft during a substrate retaining operation, the second end of the retaining member is configured to position in a normal position when the first end of the retaining member properly retains the treatment target substrate, and the second end of the retaining member is configured to position in an abnormal position when the first end of the retaining member does not properly retain the treatment target substrate; the treatment apparatus further comprising: a touch sensor fixed on a bottom of the casing and configured to touch a portion of the retaining member under a predetermined condition while the retaining member is being rotated, wherein the touch sensor is arranged adjacent to the second end of the retaining member in such a way that at least a portion of the touch sensor touches the second end of the retaining member while the retaining member is being rotated when the second end of the retaining member is in the abnormal position, thereby detecting that the first end of the retaining member does not properly retain the treatment target substrate.
 2. The treatment apparatus of claim 1, wherein the touch sensor has a touch portion having flexibility, the touch portion being adapted to touch the second end of the retaining member, and a sensor portion connected to the touch portion to detect a movement of the touch portion.
 3. The treatment apparatus of claim 2, wherein the touch portion has a protrusion protruding toward the retaining member so that the protrusion can touch the second end of the retaining member, the protrusion being replaceable.
 4. The treatment apparatus of claim 2, wherein the sensor portion is installed outside the casing.
 5. The treatment apparatus of claim 1, further comprising a control mechanism to control at least the rotation mechanism, the control mechanism rotating the substrate-retaining mechanism once at a rate lower than a rotation rate when the treatment target substrate is treated, after the treatment target substrate has been retained by the substrate-retaining mechanism, so as to check whether or not the treatment target substrate is properly retained by the substrate-retaining mechanism. 